Microsoft Windows 2000 contains support for Accessibility options within the operating system. Accessibility support is a series of assistive technologies within Windows that allow users with disabilities to still be able to access the functions of the operating system. Accessibility support is enabled or disabled through shortcuts built into the operating system, or through the Accessibility Utility Manager. Utility Manager is an accessibility utility that allows users to check the status of accessibility programs (Microsoft Magnifier, Narrator, On–Screen Keyboard) and to start or stop them.

There is a flaw in the way that Utility Manager handles Windows messages. Windows messages provide a way for interactive processes to react to user events (for example, keystrokes or mouse movements) and communicate with other interactive processes. A security vulnerability results because the control that provides the list of accessibility options to the user does not properly validate Windows messages sent to it. It's possible for one process in the interactive desktop to use a specific Windows message to cause the Utility Manager process to execute a callback function at the address of its choice. Because the Utility Manager process runs at higher privileges than the first process, this would provide the first process with a way of exercising those higher privileges. ...continued....

Microsoft Security Bulletin MS03-024
Buffer Overrun in Windows Could Lead to Data Corruption

Server Message Block (SMB) is the Internet Standard protocol that Windows uses to share files, printers, serial ports, and to communicate between computers using named pipes and mail slots. In a networked environment, servers make file systems and resources available to clients. Clients make SMB requests for resources, and servers make SMB responses in what’s described as a client server request-response protocol.

A flaw exists in the way that the server validates the parameters of an SMB packet. When a client system sends an SMB packet to the server system, it includes specific parameters that provide the server with a set of “instructions.” In this case, the server is not properly validating the buffer length established by the packet. If the client specifies a buffer length that is less than what is needed, it can cause the buffer to be overrun.

By sending a specially crafted SMB packet request, an attacker could cause a buffer overrun to occur. If exploited, this could lead to data corruption, system failure, or—in the worst case—it could allow an attacker to run the code of their choice. An attacker would need a valid user account and would need to be authenticated by the server to exploit this flaw....continued...

All versions of Microsoft Windows contain support for file conversion within the operating system. This functionality allows users of Microsoft Windows to convert file formats from one to another. In particular, Microsoft Windows contains support for HTML conversion within the operating system. This functionality allows users to view, import, or save files as HTML.

There is a flaw in the way the HTML converter for Microsoft Windows handles a conversion request during a cut-and-paste operation. This flaw causes a security vulnerability to exist. A specially crafted request to the HTML converter could cause the converter to fail in such a way that it could execute code in the context of the currently logged-in user. Because this functionality is used by Internet Explorer, an attacker could craft a specially formed Web page or HTML e-mail that would cause the HTML converter to run arbitrary code on a user's system. A user visiting an attacker’s Web site could allow the attacker to exploit the vulnerability without any other user action...continued..